Commit b0343ab3 authored by Russell King's avatar Russell King Committed by Russell King (Oracle)
Browse files

ARM: reduce the information printed in call traces 



A while back, Linus complained about the numeric values printed by the
ARM backtracing code. Printing these values does not make sense if one
does not have access to the kernel ELF image (as is normally the case
when helping a third party on a mailing list), but if one does, they
can be very useful to find the code, rather than searching for the
function name, and then doing hex math to work out where the backtrace
entry is referring to.

Provide an option to control whether this information is included,
which will only be visible if EXPERT is enabled.

Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
parent 3d14751f

arch/arm/Kconfig.debug

+11 −0
Original line number Diff line number Diff line
@@ -81,6 +81,17 @@ endchoice 
config ARM_UNWIND

	bool



config BACKTRACE_VERBOSE

	bool "Verbose backtrace"

	depends on EXPERT

	help

	  When the kernel produces a warning or oops, the kernel prints a

	  trace of the call chain. This option controls whether we include

	  the numeric addresses or only include the symbolic information.



	  In most cases, say N here, unless you are intending to debug the

	  kernel and have access to the kernel binary image.



config FRAME_POINTER

	bool

arch/arm/kernel/traps.c

+5 −3
Original line number Diff line number Diff line
@@ -67,12 +67,14 @@ void dump_backtrace_entry(unsigned long where, unsigned long from, 
{

	unsigned long end = frame + 4 + sizeof(struct pt_regs);



#ifdef CONFIG_KALLSYMS

#ifndef CONFIG_KALLSYMS

	printk("%sFunction entered at [<%08lx>] from [<%08lx>]\n",

		loglvl, where, from);

#elif defined CONFIG_BACKTRACE_VERBOSE

	printk("%s[<%08lx>] (%ps) from [<%08lx>] (%pS)\n",

		loglvl, where, (void *)where, from, (void *)from);

#else

	printk("%sFunction entered at [<%08lx>] from [<%08lx>]\n",

		loglvl, where, from);

	printk("%s %ps from %pS\n", loglvl, (void *)where, (void *)from);

#endif



	if (in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE))